Question

Ma ajuta cineva la ex 7 va rog​

Answer 1

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Answer 2

Răspuns:

$|\overrightarrow{AB}+\overrightarrow{AC}|^2=\left(\overrightarrow{AB}+\overrightarrow{AC}\right)\left(\overrightarrow{AB}+\overrightarrow{AC}\right)=|\overrightarrow{AB}|^2+2\overrightarrow{AB}\cdot\overrightarrow{AC}+|\overrightarrow{AC}|^2=\\=9+0+16=25\Rightarrow |\overrightarrow{AB}+\overrightarrow{AC}|=5$

Produsul scalar al vectorilor $\overrightarrow{AB}, \ \overrightarrow{AC}$ este 0, deoarece vectorii sunt perpendiculari.

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